NAME

Tk::Autoscroll - space invaders-like scrolling

SYNOPSIS

    use Tk::Autoscroll;
    Tk::Autoscroll::Init($widget);

DESCRIPTION

This lets you enable scrolling similar to the one in Microsoft Explorer. Press the middle mouse button and then move the mouse to scroll the widget. A further press on the middle button stops the scrolling.

It is also possible to use the autoscrolling feature for all Scrolled() widgets automatically. To do so, you have to write

    use Tk::Autoscroll 'as_default';

FUNCTIONS

Init($widget, [options ...])

Possible options:

-trigger: Default value is ``<Button-2>''
-stoptrigger: An event to stop autoscrolling. Normally, this is not defined meaning that autoscrolling will stop if Button-2 is pressed again. If -stoptrigger is set to <ButtonRelease-2>, then the user have to hold the middle button down to autoscroll and autoscrolling will stop if the user releases the button.
-speed: Values are ``slow'', ``normal'' and ``fast''. Default value is ``normal''.
-beforestartcommand, -afterstartcommand, -beforestopcommand, -afterstopcommand: Commands which are executed before/after beginning/ending autoscroll operation. Note that only subroutine references are allowed, but not perl/Tk callbacks (i.e. the [ ] notation). The ``-before'' callbacks should return true, otherwise the operation is cancelled.

If you want to apply any Init options to all widgets when using as_default, then you can define the global variable @default_args. Example:

    @Tk::Autoscroll::default_args = (-stoptrigger => '<ButtonRelease-2>');

`Reset($widget)`

Remove the binding, scrolling is not possible anymore.

BUGS

The import() function could be better implemented, i.e. avoiding the duplicate of Scrolled() definition.

Any motion binding for the widget is overwritten.

Reset() should probably restore all used bindings.

AUTHOR

Slaven Rezic <slaven@rezic.de>

COPYRIGHT

Tk::Autoscroll - space invaders-like scrolling